Summary Air Cargo Carriers, Inc. Flight SNC2917, a Short Brothers SD3-60 aircraft (registrationN748CC, serial numberSH3748), was on a charter cargo flight from Toledo, Ohio, USA, to Oshawa, Ontario, with two pilots on board. The crew conducted an instrument flight rules approach to Oshawa Municipal Airport in night instrument meteorological conditions. At approximately 2000eastern standard time, the aircraft landed on Runway30, which was snow-covered. During the landing roll, the pilot flying noted poor braking action and observed the runway end lights approaching. He rejected the landing and conducted a go-around procedure. The aircraft became airborne, but it started to descend as it flew over lower terrain, striking an airport boundary fence. It continued until it struck rising terrain and then a line of forestation, where it came to an abrupt stop. The flight crew exited the aircraft and waited for rescue personnel to render assistance. The aircraft was substantially damaged, and both pilots sustained serious injuries. There was no post-crash fire. Ce rapport est galement disponible en franais. Other Factual Information History of the Flight The flight crew members started their day conducting a flight from Detroit, Michigan, to Rockford, Illinois, USA, to pick up freight. The aircraft was then flown to Windsor, Ontario, where the freight was unloaded. The next flight was to Toledo, Ohio, where the aircraft was loaded with nine pallets of autoparts destined for Oshawa, Ontario. It was planned that the last two flights of the day would be from Oshawa to Toronto/LesterB. Pearson International Airport, Ontario, to pick up more freight, and then to Detroit, where the flight crew members would end their duty day. The first officer was the pilot flying for the flight from Toledo to Oshawa. Air traffic control advised the flight crew to anticipate the localizer backcourse Runway30 approach at Oshawa Municipal Airport. The flight crew members were given radar vectors and then cleared for the straight-in approach. During the approach, the first officer had difficulty maintaining the backcourse localizer, and the captain took control when the aircraft was 3to 4miles from touchdown. While descending on the approach, the flight crew selected 15of flap and maintained VREF+ 10knots, that is 110knots indicated airspeed (KIAS). At approximately 900feet above sea level (asl), about 440feet above ground level (agl), the flight crew observed the runway edge lights to the right of the aircraft. The captain realigned the aircraft to the runway centreline and continued the approach. The aircraft touched down at about 2000eastern standard time,1 approximately one-third of the way down the runway. After touchdown, the captain selected full reverse. He noted that the rate of deceleration was slower than expected and observed the end of the runway approaching. After 5to 8seconds of full-reverse application, he called for a go-around, and the power levers were advanced to maximum take-off power. With little runway remaining and without referencing the airspeed indicator, the captain rotated to a take-off attitude; the aircraft became airborne prior to the end of the runway. The captain attempted to fly the missed approach; however, after the aircraft flew past level terrain at the end of the runway, it descended and the tail struck the airport perimeter fence. The aircraft flew over a marshy area, the landing gear struck rising, hilly terrain, and the aircraft then struck a line of forestation, coming to an abrupt stop at about2001. The cockpit area was wedged between two cedar trees; however, the flight crew evacuation was not hampered. The controller saw the aircraft roll through the runway intersection; however, he did not observe the aircraft conducting the go-around. The emergency locator transmitter sounded, probably when the aircraft struck the trees. Air Traffic Control and SNC2917 Air traffic control communications with SNC2917were normal during the approach and landing. The following information is relative to the occurrence and the crew's decisions. At about 1949, 11minutes before the aircraft landed, the Oshawa tower controller transmitted to the aircraft that there was a layer [of cloud] at about 100feet, visibility mile. During the approach, SNC2917 had requested a runway condition report (RCR). At about 1957:30, the tower controller transmitted to the aircraft that the RCR was just completed, that the runway was reported snow-covered and slippery underneath, and that the aircraft was cleared to land. At 1958:28, SNC2917 requested that the lights be turned up. The controller responded that the runway lights were at 5(highest) and that the runway identification lights and precision approach path indicators were at 3(highest). None of the airport vehicles was equipped with decelerometer equipment and, therefore, a Canadian Runway Friction Index report could not be provided to the tower. A runway surface condition report was completed and transmitted to the tower, indicating that 100percent of the runway was covered with inch of slush/wet snow. The information transmitted to the tower was that the runway was snow-covered and quite slippery underneath. Personnel Information The captain held a valid airline transport pilot licence. He was certified and qualified for the flight, and had accumulated over 5300hours of total flying time, 1000of which were on the Short Brothers SD3-60 aircraft. He had been awake for 13hours and had been performing duties as a flight crew member for 10hours before the occurrence. The captain was seated in the left seat and was the pilot flying during the occurrence. The first officer held a valid commercial pilot licence. He also was certified and qualified for the flight, and he had accumulated 800 hours of total flying time, 400of which were on the Short Brothers SD3-60 aircraft. He had been awake for 12hours and had been performing duties as a flight crew member for 9hours before the occurrence. The first officer was seated in the right seat and was the pilot not flying. Airport Information Oshawa Municipal Airport is at an elevation of 459feet asl and has two asphalt-surfaced runways (seeAppendixA). The runway in use, Runway30, is 4000feet long and 100feet wide. The airport has three instrument approaches; the aircraft conducted the LOC (BC)/DMERWY30 non-precision instrument approach (seeAppendixB). The minimum descent altitude and advisory visibility for this approach are 820 feet asl (373feetagl) and 1statute miles (sm). The terrain past the end of Runway30 is level for approximately 200feet. It then slopes down for the next 150feet to the airport perimeter fence. Beyond the fence, the terrain continues a downslope for 75feet before it levels to a 25-foot marshy area. There is then 100feet of rising, hilly terrain before a line of forestation consisting of large cedar trees is encountered. The elevation of this area is approximately 449feetasl. Meteorological Information There was no weather reporting facility at Oshawa Municipal Airport. The 2000aviation routine weather report (METAR) for Toronto/Buttonville Airport (approximately 22nautical miles west of Oshawa) reported the wind from 230True at 14knots, visibility 1sm in light snow, broken ceiling at 900feet, overcast ceiling 1400feet, temperature 0C, dew point -1C, and altimeter setting29.90. The direct controller/pilot communication reported the weather at Oshawa Municipal Airport as wind from 230Magnetic at 15knots and altimeter setting29.92. Aircraft Information The aircraft was not equipped with a flight data recorder or a cockpit voice recorder, nor was either required by regulation. The weight and centre of gravity were within the prescribed limits. During the investigation, aircraft performance calculations were made. The aircraft landing weight was calculated to be approximately 19500pounds. From the aircraft performance charts, it was determined that the unfactored landing distance required for a flap-15 landing is about 2473feet. This unfactored distance reflects a dry runway, normal ambient conditions, and a perfect approach and landing. The 60percent operational factor applied to published landing distance charts is intended to cover variations in the approach and landing. The Aircraft Flight Manual (AFM) chart for a 15flap landing (Maximum Landing Weight for Landing Distance Available) requires a landing distance (factored) of about 4120feet for the aircraft's weight of 19500pounds. Using the AFM chart Effect of a Slippery Surface on Landing Distance Required and entering with the dry landing distance (4120feet), the landing distance required on a slippery runway (coefficient of friction=0.5) is about 7400feet. Although the 7400-foot figure would vary depending on the coefficient of friction at the time of landing, it is probably representative of a snow-covered, slippery runway. The AFM also states, Reverse thrust is authorised for ground manoeuvring at speeds not exceeding 40knots and Reverse thrust must not be used during a normal landing.2 On 31 March2004, the aircraft manufacturer issued All Operator Message (AOM)3 No.SD002/04 on advanced notification of impending airworthiness directive. This communiqu highlighted a remote possibility that a fatigue failure on a mid or outer flap actuator, in combination with a dormant seal failure on the same wing's outer or mid actuator, could occur, leading to a significant reduction in roll control due to flap asymmetry. Based on AOM No.SD002/04, Air Cargo Carriers, Inc. prohibited the normal use of full flap (30) on those aircraft where the life of the affected actuators could not be demonstrated to be within the declared fatigue life, and operators were required to use the mid flap setting (15) for landings. On 29September2004, the aircraft manufacturer conducted a forum in Orlando, Florida, USA, for SD3operators, which was attended by three Air Cargo Carriers, Inc. management employees. All of the operators were briefed to the effect that the aircraft manufacturer had cleared the flap actuators to match the aircraft life. Thus, the Airworthiness Directive was not going into effect, and normal use of flap 30was approved. The aircraft manufacturer also advised of its intent to test beyond aircraft life to cover the scenario of actuators moving between airframes. On 20October2004, the aircraft manufacturer issued AOM No.SD006/04, which cleared the flap actuators for a life of 100000flights and stated that, based on fleet utilization data, it is inconceivable that any actuator has attained or is likely to attain 100000flights in service in the near future. On 18November2004, the aircraft manufacturer issued AOM No.SD007/04, stating that the United Kingdom Civil Aviation Authority had agreed that the in-service life of the flap actuators need not to be tracked and that the removal of this component from the Life Limited Components section of the Aircraft Maintenance Manual would be actioned at the next appropriate manual revision. Examination of the aircraft at the occurrence site indicated that the flaps were extended approximately 15. The flap selector was found near the 30position; however, the selector was damaged during the impact and its position was considered unreliable in determining the actual flap position. The landing gear lever was in the down position and the landing gear was down and locked during the impact sequence. The aircraft tail section was damaged when it struck the perimeter fence. Both of the 6-bladed propellers struck the trees at high power, and all 12blades were broken from the propeller hubs. Ground Effect During take-offs and landings, the ground interferes with the formation of the large wing-tip vortices, the interference causing a reduction in induced drag. The effect is the greatest when very close to the ground and vanishes when the aircraft's height is approximately equal to the wingspan of the airplane. This phenomenon is known as ground effect. During take-off, if the pilot rotates the airplane to a nose-high attitude before it reaches the normal rotation speed, ground effect reduces induced drag and the airplane is able to reach a speed at which it can fly. If the pilot stays in ground effect (low), the aircraft will accelerate to normal speeds. However, if the pilot attempts to gain altitude before increasing the flying speed, ground effect diminishes, resulting in increased induced drag. The power required to fly the airplane rises sharply as the induced drag increases, and a deficit in power would result in a sink rate. As the airplane starts settling, the angle of attack is increased because of the downward movement and, since the angle was at the raw edge to begin with, the airplane stalls and contacts the ground. Some factors that may contribute to this type of accident are short runways, rough ground, grass or snow, high airport elevation, high air temperature, a weak engine, and a heavy load.